Open Source GPS HOW TOUploading GPS-Recorded Routes to the Marengo Route PlannerBy Martyn C Davis(This is the Windows version - for Mac, see here)I've been asked on several occasions how to get a recorded route OFF your GPS unit and onto the Marengo Route Planner. This is the opposite way to the methods I describe in the original HOW TO, which details how to create a route and upload it to your GPS unit. Doing it the other way is useful for several reasons: you might have ridden a nice, unplanned route, and you want to save it and program it in to your GPS. Or you might have wandered off course on a programmed ride, and you want to compare your actual route to your original planned route. OK, firstly we need to get the data out of the GPS unit. As usual, GPSBabel is our tool of choice. PLEASE NOTE that I am not affiliated with this fine piece of software. If you have questions regarding it, check their forums. Any questions regarding GPSBabel which are misdirected my way will be ignored! Right, we need to be aware of definitions. In GPSBabel, Waypoints are individual position markers. Routes are the things we create when we UPload a route to the device, and Tracks are what we are interested in here: they are what the unit stores when you are recording a route as you ride. So, in GPSBabel, we need to specify that we want to download tracks: 
See in the "What?" section, I've just got "tracks" ticked. Now, before you press "Let's Go", we need to set a filter. This is because your GPS Unit stores a trackpoint every few feet when it's recording. Which means even a short ride will have potentially thousands of points recorded. If we tried to load all of that into the Route Planner, it would (a) take forever and (b) use a LOT of resources. Plus also it would simply be overkill - you only really need points at junctions to define a route successfully. So press the "Filter" button next to the "Let's Go" button, which brings up the following dialogue: 
Notice that I've checked the "transform" option, and selected "Tracks->Routes" in the drop down. As explained above, rides are RECORDED using "tracks", but navigation is performed with "routes". Notice also that I've checked the "simplify" option and limited the route to 100 points. This works really well - gpsbabel intelligently leaves points where you (mostly) want them - where the route deviates. Now press "OK" and, when back at the original dialogue, press "Let's Go". Assuming you've got your GPS attached and there's a route on it, you should be able to save your route to a file, which you should be able to upload to the Marengo route planner. For more information, please see the forum at http://www.marengo-ltd.com/mapforum/ I'll be interested to see how it works with all different GPS units too - drop me a note to tell me what you've got it working with. Finally, you may also contact me here. Queries will be given much more attention if you accompany them with a small donation (see the PayPal link at the end of this page).
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